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Consider a normal (L1) guest running under the main hypervisor (L0), and then a nested guest (L2) running under the L1 guest which is acting as a nested hypervisor. L0 has page tables to map the address space for L1 providing the translation from L1 real address -> L0 real address; L1 | | (L1 -> L0) | ----> L0 There are also page tables in L1 used to map the address space for L2 providing the translation from L2 real address -> L1 read address. Since the hardware can only walk a single level of page table, we need to maintain in L0 a "shadow_pgtable" for L2 which provides the translation from L2 real address -> L0 real address. Which looks like; L2 L2 | | | (L2 -> L1) | | | ----> L1 | (L2 -> L0) | | | (L1 -> L0) | | | ----> L0 --------> L0 When a page fault occurs while running a nested (L2) guest we need to insert a pte into this "shadow_pgtable" for the L2 -> L0 mapping. To do this we need to: 1. Walk the pgtable in L1 memory to find the L2 -> L1 mapping, and provide a page fault to L1 if this mapping doesn't exist. 2. Use our L1 -> L0 pgtable to convert this L1 address to an L0 address, or try to insert a pte for that mapping if it doesn't exist. 3. Now we have a L2 -> L0 mapping, insert this into our shadow_pgtable Once this mapping exists we can take rc faults when hardware is unable to automatically set the reference and change bits in the pte. On these we need to: 1. Check the rc bits on the L2 -> L1 pte match, and otherwise reflect the fault down to L1. 2. Set the rc bits in the L1 -> L0 pte which corresponds to the same host page. 3. Set the rc bits in the L2 -> L0 pte. As we reuse a large number of functions in book3s_64_mmu_radix.c for this we also needed to refactor a number of these functions to take an lpid parameter so that the correct lpid is used for tlb invalidations. The functionality however has remained the same. Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
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| .. | ||
| 8xx_mmu.c | ||
| 40x_mmu.c | ||
| 44x_mmu.c | ||
| copro_fault.c | ||
| dma-noncoherent.c | ||
| drmem.c | ||
| dump_hashpagetable.c | ||
| dump_linuxpagetables.c | ||
| fault.c | ||
| fsl_booke_mmu.c | ||
| hash64_4k.c | ||
| hash64_64k.c | ||
| hash_low_32.S | ||
| hash_native_64.c | ||
| hash_utils_64.c | ||
| highmem.c | ||
| hugepage-hash64.c | ||
| hugetlbpage-book3e.c | ||
| hugetlbpage-hash64.c | ||
| hugetlbpage-radix.c | ||
| hugetlbpage.c | ||
| init_32.c | ||
| init_64.c | ||
| init-common.c | ||
| Makefile | ||
| mem.c | ||
| mmap.c | ||
| mmu_context_book3s64.c | ||
| mmu_context_hash32.c | ||
| mmu_context_iommu.c | ||
| mmu_context_nohash.c | ||
| mmu_context.c | ||
| mmu_decl.h | ||
| numa.c | ||
| pgtable_32.c | ||
| pgtable_64.c | ||
| pgtable-book3e.c | ||
| pgtable-book3s64.c | ||
| pgtable-hash64.c | ||
| pgtable-radix.c | ||
| pgtable.c | ||
| pkeys.c | ||
| ppc_mmu_32.c | ||
| slb_low.S | ||
| slb.c | ||
| slice.c | ||
| subpage-prot.c | ||
| tlb_hash32.c | ||
| tlb_hash64.c | ||
| tlb_low_64e.S | ||
| tlb_nohash_low.S | ||
| tlb_nohash.c | ||
| tlb-radix.c | ||
| vphn.c | ||
| vphn.h | ||